p-nitrosoanilino benzothiazoles



2,976,292 p-NITROSOANILINO BENZOTHIAZOLES Ching C. Tung, Kirkwood, Mo., and John J. DAmico, Charleston, W. Va.*, assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Nov. 28, 1958, Set. No. 776,766 Claims. (Cl. 260- 305,)

The present invention relates to a new class of com pounds. More particularly, the invention relates to p-nitrosanilino 'benzoth-iazoles of the general formula where X represents hydrogen, halogen, alkyl, alkoxy, nitro or phenyl and Y represents hydrogen, alkyl or nitroso. Examples of alkyl radicals include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl and n-amyl. Examples of alkoxy radicals include methoxy, 'ethoxy, n-propoxy, isopropoxy and n-butoxy. The nitroso'phenyl radical may contain substituents in the meta but not the ortho position, particularly lower alkyl, lower alkoxy or halogen. Thus, Z represents lower alkyl, lower alkoxy, halogen or hydrogen.

The new compounds are readily prepared 'by the condensation of a 2-halogen arylene thiazole with aniline or N-substituted secondary aniline having a reactive hydrogen and treating the product with cold nitrous acid.

The required intermediates have been described but lack significant biological activitywhereas the new compounds find application for the destruction of undesired vegeta-- tion, and microorganisms. pounds comprise 6-ethoxy-2-(N-methyl-p-nitrosoanilino) benzothiazole,

. 4-phenyl-2-(N-methyl-p-nitrosoanilino)benzothiazole,

5 -nitro-2- (N-methyl-p -nitrosoanilino benzothiazole, 4-methyl-2- (N rnethyl-p-nitrosoanilino) benzothiazole, 2- (p-nitrosoanilino) benzothiazole, 2(N-methyl-p-nitrosoanilino)benzothiazole,

5 -chloro-2- (N-methyl-p-nitrosoanilino) benzothiazole, 5 -chloro-2- (N-ethyl-p-nitrosoanilino) benzothiazole, 2-(N-ethyl-p-nitrosoanilino)benzothiazole,

' 2- (N-methyl-3-methyl-4-nitrosoanilino benzothiazole,

- To 214.3 grams (2.0 moles) of N-methyl aniline at 80 C. was added dropwise at 80-100 C. during 15. minutes 169.63 grams (1.0 mole) of 2-chlorobenzothiazole. Thestirred reaction mixture was heated at 140- 150 C.'for 6 hours' After cooling to 90 C., 500 ml. of water'was added and stirring continued for 30 minutes.

Examples of the new com- United States, Patent perature,

,to wild oats and pigweed. .In lower concentrationsdh The top aqueous layer was decanted and the bottom organic layer dissolved in-500 ml. of chloroform. The

'crystallizationfrom ethyl alcohol itmelted at 44-46 ,C..

ent 2-(N-methyl-p-nitrosoanilino)benzothiazole 'wa'sjse-g I nitrosoanilino')benzothiazole controlled I fusarium wilt o tomatoes at 0.01 %".concentration andwas'fairly'eifective at 0.001%. 2-(N-methy1-p-nitrosoanilin o)'benzothiazole Patented Mar. 21, [rest excess or unreacted N-methyl aniline was rem ve by distillation at 3 mm. at a maximum pot temperature-of 225 C. The 2-(N-mehtylanilino)benzothiazole so. obtained was a viscous oil which solidified on standing. To 40 grams (0.166 mole) of this thiazole was added. with stirring 250 ml. of ethyl alcohol, '68 mlof concentrated hydrochloric acid and 250 grams of ice. To. this cold solution was added dropwise at 0-5 C1 in 10 minutes 12 grams (0.168 mole) of 97% sodium nitrite dissolved in 20 ml. of water. The mixture was stirred at 0-l0 C. for one hour, then 25% sodium hydroxide. added dropwise at 10-20 C. until a pH of 8 was obtained. Stirring was continued for another hour at 10- 20 C. and the resulting precipitate filtered, washed with water until free'of chloride and air dried at room tem- The 2-(N-methyl-p-nitrosoanilo)henzothiazole was a green solid melting at -72 C. after recrystallization from ethyl alcohol. Analysis gave 11.6% sulfur as compared to 11.9% calculated for C H N OS.

Example '2 2,5-dichlorobenzothiazole' was substituted for Z-chlorobenzothiazole in the procedure of Exampleli The charge of 2,5-dichlorobenzothiazole was 102.04 "grams (0.5 mole), yielding S-chloro-Z-(N-methylanilino)benzothiazole. To a reactor was-charged 68.7 grams (0.25 mole) of the 5-chloro-2-(N-methylanilino)benzothiazole so obtained, 250 ml. of ethyl alcohol, 250 grams of ice, 1 1 8.5 grams (0.26 mole) of 97% sodium nitrite dissolved I in 30 ml. of water and enough 25% sodium hydroxide to s 3 give a pH of 8. The 5-chloro-2-(N-methyl-p-nitroso- *anilino)benzothiazole isolated by the procedure of Example 1 was a green solid and was obtained in 96% theory yield. After recrystallization from ethyl alcohol: it melted at 68-70 C. Analysis gave 10.8% sulfur and 12.1% chlorine as compared to 10.6% sulfur and 11.7%

chlorine calculated for C H ClN OS. i

Example 3 addition; which required 10 minutes, the temperature was held at 0-10 C. Stirring was continued. at this temper ature for an additional'hour and then 25% sodium 'hy"-j droxide was added dropwise at 0l5 C.- until a pl-I'of 8 was obtained. After stirring for air-hour atYO-IOSIC, the precipitate was collected by filtration, washed with; one liter of water and air dried at 25-30 C. The 5- chloro-2-(N-ethyl-p-nitrosoanilino)benzothiazolewas .obtained as a dark brownfsolid in 97.5% yield. Aiter' re- Analysis'gave 10.7% sulfur as compared to l0.1%"cjal culated for C I-I gClN OS. i The p-nitrosoanilino benzothiazoles as disclosed herein are of utility in many important applications. Applied as'a foilagespray containing 0.5% of thieflactive ingredi:

verely toxic to =broadleaf plants and some grasses, espe-f cially, cra'ograss. In pre-ernergen'ce application at pounds per acre thesame compound was severelytoxio compounds are useful'for combating plant diseases fan microorganisms] For example, 5-chloro-2-(N5rnethyl-p centration of 0.001% 2-(N-methyl-p-nitrosoanilino)henzothiazole prevented growth of Staphylococcus aureus.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which doe not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A compound of the structure C-N NO N where X is selected from the group consisting of hydrogen, halogen, lower alkyl, lower alkoxy, nitro and phenyl, Y is selected from the group consisting of hydrogen, lower alkyl and nitroso and Z is selected from the group consisting of lower alkyl, lower alkoxy, halogen and hydrogen.

2. A compound of the structure Z s f I where X and Z are hydrogen and Y is lower alkyl.

3. A compound of the structure Z S r 1 C-N- NO Q) Q X where X is halogen, Y is lower alkyl and Z is hydrogen.

4. A compound of the structure S ICH:

CN NO N Q 5. A compound of the structure s (3112 C1 N No references cited. 

1. A COMPOUND OF THE STRUCTURE 